THE AMOEBAE 



149 



dogs with cultured protozoa but failed to 

 infect 3 young dogs, a young wolf and 2 

 humans. In view of the affection with 

 which some dog and cat owners treat their 

 pets, there is no reason to believe that the 

 entamoebae in the mouths of these animals 

 are a different species from that of man. 



no cysts. Simitch (1938a) was unable to 

 infect horses with E. gingivalis (syn. , 

 E. canibuccalis ) from the dog or to infect 

 dogs with the horse form. Hence he con- 

 sidered the latter to be a new species. 

 Further study is needed to learn whether 

 this view is correct. 



Kirby (1928) found E. gingivalis in 

 the mouths of 2 chimpanzees with pyorrhea. 

 Kofoid, Hinshaw and Johnstone (1929) 

 found it in the mouths of Macaco mulatta 

 and M. iriis. Deschiens and Gourvil (1930) 

 found it in the M. ))ii(latta and Papio 

 sphynx. Hegner and Chu (1930) found it in 

 the mouths of 37 out of 44 wild M. philip- 

 pinensis. 



E. gingivalis has no cysts. The tro- 

 phozoites are usually 10 to 20j:i long, but 

 may range from 5 to 35/^. The cytoplasm 

 consists of a zone of clear ectoplasm and 

 granular endoplasm containing food vac- 

 uoles. The amoebae usually feed on leuco- 

 cytes, epithelial cells, sometimes on bac- 

 teria and rarely on red blood cells. There 

 are usually a number of pseudopods. The 

 nucleus is 2 to 4 |U in diameter, with a 

 moderately small endosome, a peripheral 

 layer of chromatin granules and some del- 

 icate achromatic strands extending from 

 the endosome to the nuclear membrane. 



Reproduction is by binary fission. It 

 was described in detail by Child (1926), 

 Stabler (1940) and Noble (1947). Child 

 said that 6 chromosomes are present, but 

 Stabler and Noble found only 5. 



ENTAMOEBA EQUIBUCCALIS 

 SIMITCH, 1938 



Synonym : Entamoeba gingivalis va.r . 

 eqiii. 



Nieschulz (1924) found this amoeba in 

 the mouths of several horses in Holland, 

 and Simitch (1938a) cultured it from the 

 mouths of 16 out of 22 mares and 3 out of 

 4 donkeys in Serbia. It is morphologically 

 identical with E. gingivalis, except that 

 its trophozoites are somewhat smaller, 

 measuring 7 to 14jj, in diameter. It has 



ENTAMOEBA SUIGINGIVALIS 

 TUMKA, 1959 



Tumka (1959) found this amoeba on the 

 coating of the teeth of 6 out of 32 domestic 

 pigs from the vicinity of Leningrad. It re- 

 sembles E. gingivalis but is in its lower 

 size range, measuring 7 to 12fi with a 

 mean length of 9 jj, when fixed and stained. 

 It is questionable whether this is a sepa- 

 rate species. 



ENTAMOEBA CAUDATA 

 CARINI AND REICHENOW, 1949 



This species was found in the feces 

 of a dog in Brazil. No cysts were seen. 

 The trophozoites were 10 to 36 fi long. 

 Their pseudopods and nuclei resembled 

 those of E. histolytica, but they differed 

 from it in containing many ingested bac- 

 teria and in having a sac-like appendage 

 at the posterior end containing dense, 

 darkly staining cytoplasm and undigested 

 bacteria. 



ENTAMOEBA GEDOELSTI 

 (HSIUNG, 1930) 



Synonym: Endamoeba gedoelsti. 



Hsiung (1930) found this amoeba in 

 the cecum or colon of 7 out of 46 horses 

 in Iowa. What was probably the same spe- 

 cies had been seen in the horse by Gedoelst 

 (1911) in Belgium and Fantham (1920) in 

 South Africa. No cysts have been seen. 

 The trophozoites are 7 to 13 |i long and 

 contain bacteria in their food vacuoles. 

 The nucleus is similar to that of E. coli, 

 with an eccentric endosome surrounded 

 by a halo and a row of peripheral chromatin 

 granules. 



